Conventional information retrieval (IR) systems combine free text search with contextual navigation to enhance the user experience. For example, a website that sells products provides a keyword search interface to search a database of documents associated with the products being sold, and the interface is combined with a browsing menu that allows users to drill down into several levels of categories of the products. In response to a user issuing a keyword query to search the database, the IR system presents the user with a set of relevant documents as a result of that query, and also changes the navigation menu to display the most relevant facets for the given query. Improvements are needed relative to the speed at which these known IR systems present the keyword search results and update the contextual navigation menu. Further, the development efforts required to combine free text search with contextual navigation are significant. Thus, there exists a need to overcome at least one of the preceding deficiencies and limitations of the related art.